docs: def get_metadata(self, refresh=True):
          """
          return cached metadata by default
  
          :param refresh: bool, update the metadata with up to date content
          :return: dict
          """
          if refresh or not self._metadata:
              ident = self._id or self.get_full_name()
              if not ident:
                  raise ConuException(
                      "This image does not have a valid identifier.")
              self._metadata = dict()
          return self._metadata